Telephone-transmitter.



No. 644,652. Patented Mar. 6, I900. J. M. W'ILDERMAN &. E. A. NELSON.

TELEPHONE TRANSMITTER.

(Application filed Aug. 24, 1899.) (No Model.)

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UNITED STATES PATENT ()EEICE.

JOSEPH M. WILDERMAN AND ENooH A. NELSON, OF ST. CHARLES, MISSOURI.

TELEPHONE-TRANSMITTER.

SPECIFICATION forming part of Letters Patent No. 644,652, dated March 6, 1900. Application filed August 24, 1899. Serial No. 728,276. (No model.)

To all whom it may concern:

Beit known that we,J0sEPH M.WILDERMAN and ENOOH A. NELsoN, citizens of the United States, residing in the city and county of St. Charles, in the State of Missouri, have invented a new and useful Telephone-Transmitter, of which the following is a specification.

Ourinvention relates to telephones, and has for its object to prevent packing of the comminuted particles of the transmitter.

To this end it consists in the arrangements and combinations hereinafter described and claimed.

In the accompanying drawings, which form part of this specification and wherein like symbols refer to like parts wherever they occur, Figure I is a vertical section of ourdevice. Fig. II is a horizontal section thereof on the line II II of Fig. I, and Fig. III is a sectional view on the line III III of Fig. II looking to the right.

It is well known that carbon in the form of dust or comminuted particles has important advantages as the variable-resistance element of a transmitting-telephone. Such dust or particles are, however, very likely to pack or cake into one coherent mass, and thereby lose their characteristic advantages. This packing is due to the fact that the casing 1 for the carbon particles is fixed and the front plate thereof is mounted on the diaphragm of the transmitter, whereby the particles are subjected to the vibrating action of said front plate without any other alternation of their respective positions. It is the object of the present invention to avoid such packing by providing for the automatic shifting of the particles relatively to each other.

In the ordinary telephone outfit the receiver when not in use rests upon a hook or circuitchanging lever 2. This lever is provided with a spring 3, so arranged and of such strength as to raise the free outer end of the lever when such is not weighted, but to yield and let said end down when the receiver rests thereon. In our invention we adopt this ordinary arrangement of hook or lever and utilize the oscillating or reciprocating motion thereof for shifting the relative positions of the carbon particles 4 of the transmitter. For this purpose the carbon-casing 1 is mounted on the end of an axle or trunnion 6, arranged to rotate in any suitable bearings. This aXle has a ratchet-wheel 7 fixed thereon, and the hook or circuit-changing lever 2 has a springpressed pawl 8 mounted thereon and adapted to engage and actuate the ratchet-wheel.

Thus each time the receiver is removed from and returned to said hook or circuit-changing lever the spring-pressed pawl 8 turns the ratchet-wheel and through it the carbon-casing. The turning of the casing keeps shift ing the particles, and thereby prevents packing or caking of the mass.

tact-plate 10, upon which bears a contact-- spring 11, fixed on the insulating-frame 12. This contact-spring 11 is connected by a short wire 13 to another contact-spring 14, adapted to contact with the circuit-changin g lever and through it with the line-wire.

The front plate 15 of the carbon-case is mounted on and electrically connected to the metallic diaphragm 15 of the transmitter. The diaphragm and carbon case are mounted in a metallic shell 16, and this shell is electrically connected at its rear side with a metal sleeve 17, mounted on the axle of the transmitter. Upon this sleeve bears a contactspring 18 in electrical connection with the battery-circuit. In other respects any suitable system of Wiring may be adopted for completing the circuits, and as such circuits and the operation of the circuit-changing lever are well known we do not consider it necessary here to describe them particularly.

The principal novelty of the circuit lies in the section thereof whose terminals are in the axle and in the arrangement whereby the oil'- cuit is extended through the transmitter without wiring and through the axle Without a variable contact. This section of the circuit may be traced as follows: Beginning with the contact-spring 11, (which is operatively connected to the system,) the circuit continues through the contact-plate 10, the rod 9 in the axle, the rear plate of the carbon-casing 1, the comminuted carbon, the front plate 15 of the carbon-casing, the transmitter-diaphragm 15, the inclosing shell 16, the sleeve 17 on the axle, and thence to the contact-spring 18, which also is operatively connected to the system.

In order to be effective in its results, the throw of the pawl should be a considerable distance. For this purpose the pawl is arranged at approximately a right angle to the body of the hook, at a considerable distance from the fulcrum thereof. It is a special advantage of the construction above described that it operates automatically every time the telephone is used and that the shifting movement is always in the same direction. It is to be understood, however, that any other connecting devices may be used in place of the pawl and ratchet described for transmitting motion from the hookv to the carboncasing. So, too, the casing may be turned by an independent lever or by hand.

What we claim is 1. A transmitting-telephone comprising a revoluble axle mounted in the frame, two metallic pieces mounted on said axle, contactsprings arranged in the transmitter-circuit and bearing flatwise against said pieces, a casing with comminuted particles therein mounted on said axle and electrically connected on opposite sides to one of said pieces and to the diaphragm, and a metallic shell in which said diaphragm is mounted, said shell being electrically connected to the other metallic piece, substantially as described.

2. A transmitting-telephone comprising a revoluble axle mounted in the frame and having a metallic sleeve thereon and a metallic rod therein, fiat contact-springs in the transmitter-circuit bearing respectively against said rod and said sleeve, a casing with comminuted particles therein mounted on said axle and connected on one side to said rod and on the other to the diaphragm, and a metallic shell in contact with said diaphragm and said sleeve, substantially as described.

3. The combination of a comminuted-resistance transmitting-telephone having its casing mounted on a revoluble axle, a receiving-telephone and a retractile lever operatively connected to said casing to turn it and arranged to support the receiving-telephone and be actuated by the weight thereof, said axle having a metallic rod therein and a me tallic sleeve thereon connected electrically to opposite sides of said casing, and stationary contact-springs bearing flatwise on said rod and said sleeve respectively whereby they are incorporated in the transmitter-oircuit, substantially as described.

4. The combination of a comminuted-resistance transmitting-telephone whose casing is mounted on a revoluble axle, a ratchetwheel fixed on said ax1e,a receiving-telephone, and a retractile lever having a pawl thereon adapted to cooperate with said ratchet-wheel, said lever being arranged to support the receiving-telephone and be actuated by the weight thereof, said axle having two metallic pieces forming part of the transmitter-circuit, and contact-springs bearing flatwise thereon for connecting them to the fixed portions thereof, substantially as described.

JOSEPH M. WILDERMAN. ENOCH A. NELSON.

In presence of- HY E. VOGELSMEIER, FRED KNooP. 

